Modified polyisobutylene succinimide dispersants having improved seal, sludge, and deposit performance

ABSTRACT

A composition suitable for reducing sludge and degradation of elastomer seals in engines comprises an oil of lubrication viscosity and a minor amount of a sludge preventing/seal protecting nitrogen containing dispersant, which is a reaction product of a hydrocarbyl-substituted succinic acylating agent having a limited amount of low molecular weight substituent; and a polyamine or condensed polyamine containing less than 20 mole percent of polyamine components of 6 or fewer nitrogen atoms.

FIELD OF THE INVENTION

[0001] Internal combustion engines operate under a wide range oftemperatures including low temperature stop and go service as well ashigh temperature conditions produced by continuous high speed driving.Stop and go driving, particularly during cold, damp weather conditions,leads to formation of a sludge in the crankcase and in the oil passagesof a gasoline or a diesel engine. This sludge seriously limits theability of the crankcase oil to lubricate the engine effectively. Inaddition, the sludge with its entrapped water tends to contribute torust formation in the engine. These problems tend to be aggravated bythe manufacture's lubrication service recommendations which specifyextended drain oils.

[0002] Another problem facing the lubricant manufacturer is that of sealdeterioration in the engine. All internal combustion engines useelastomer seals, such as Viton™ seals, in their assembly. Over time,these seal are susceptible to serious deterioration caused by thelubricating oil composition and the deterioration results in oil leakingfrom the engine. A lubricating oil composition that degrades theelastomer seals in an engine is unacceptable to engine manufacturers andhas limited value.

BACKGROUND OF THE INVENTION

[0003] It is known to employ nitrogen containing dispersants and/ordetergents in the formulation of crankcase lubricating oil compositions.Many of the known dispersant/detergent compounds are based on thereaction of an alkenylsuccinic acid or anhydride with an amine orpolyamine to produce an alkylsuccinimide or an alkenylsuccinamic acid asdetermined by selected conditions of reaction.

[0004] U.S. Pat. No. 4,558,170 (Chen et al., Dec. 10, 1985) is directedto polyisobutylene prepared from a mixed C₄ hydrocarbon feedstream usingan AlCl₃—HCl catalyst system wherein the HCl is introduced separatelyinto the feedstream to form organochloride in the feedstream. Polymerproduct having a very narrow molecular weight distribution is obtainedover the Mn range of 700 to 3,000. Dispersants derived from thispolyisobutylene are said to exhibit substantially improved performancein lubricating oil compositions.

[0005] U.S. Pat. No. 5,614,480 (Salomon et al., Mar. 25, 1997) describesa lubricating oil composition which comprises a major amount of an oilof lubricating viscosity and

[0006] (A) at least about 1% by weight of at least one carboxylicderivative composition produced by reacting

[0007] (A-1) at least one substituted succinic acylating agentcontaining at least about 50 carbon atoms in the substituent with

[0008] (A-2) from about 0.5 equivalent up to about 2 moles, perequivalent of acylating agent (A-1), of at least one amine compoundcharacterized by the presence within its structure of at least one HN<group; and

[0009] (B) at least one alkali metal overbased salt of ahydrocarbyl-substituted carboxylic acid or a mixture of a hydrocarbylcarboxylic acid and a hydrocarbyl-substituted sulfonic acid having ametal ratio of greater than 2 in an amount sufficient to provide atleast about 0.002 equivalent of alkali metal per 100 grams of thelubricating oil composition wherein the hydrocarbyl substituent of thecarboxylic acid contains at least about 50 carbon atoms.

[0010] U.S. Pat. No. 5,792,730 (Gutierrez et al., Aug. 11, 1998) isdirected to the reaction product of hydrocarbons or polymersfunctionalized by halogenation (e.g. chlorination), thermal “ene”reaction or free radical grafting and derivatized with a heavypolyamine. A heavy polyamine is a mixture of polyalkylenepolyaminescomprising small amounts of lower polyamine oligomers such astetraethylene pentamine and pentahexamine but primarily oligomers with 7or more nitrogens, 2 or more primary amines per molecule, and moreextensive branching than conventional polyamine mixtures.

[0011] U.S. Pat. No. 5,936,041 (Diana et al., Aug. 10, 1999) pertains toimproved lubricating oil dispersants wherein a fractionating polymer isprepared prior to functionalization (e.g. in the Koch reaction) formaking dispersant additives. In one aspect, it was discovered that byfractionating a polymer to remove light hydrocarbon and unreactedmonomer from the polymer before the carbonylation step of the Kochreaction, the amount of light ester impurities generated was minimized.Light ester is an undesirable byproduct that adversely affects therecycle of the catalyst from the functionalization step of the Kochreaction. The reference also pertains to improved lubricating oilnitrogen-containing dispersant additives derived from fractionatedpolymer.

SUMMARY OF THE INVENTION

[0012] The present invention provides a composition suitable forreducing engine sludge and degradation of elastomer seals comprising

[0013] a major amount of an oil of lubricating viscosity and

[0014] a minor amount of a nitrogen-containing dispersant wherein thenitrogen containing dispersant is a reaction product of

[0015] (I) a hydrocarbyl-substituted succinic acylating agent, whereinno more than about 20 mole percent, e.g., 15 to 20 mole percent, of theindividual molecules thereof have a hydrocarbyl substituent with amolecular weight of less than 500; wherein the hydrocarbyl substituentis a polymeric species consisting essentially of olefin monomer units ofat least 3 carbon atoms; and

[0016] (II) at least one polyamine, wherein the polyamine is

[0017] (a) a polyalkylene amine containing at least one H—N< group; or

[0018] (b) a condensate of (i) a polyalkylene amine containing at leastone H—N< group with (ii) at least one alcohol containing at least oneether group, amine group, nitro group, or additional alcohol group;

[0019] wherein in said polyamine (a) or condensed polyamine (b) no morethan about 20 mole percent of the molecules contain 6 or fewer nitrogenatoms.

[0020] By means of an alternative description, thehydrocarbyl-substituted succinic acylating agent (I) is an agent whereinthe hydrocarbyl substituent is prepared from a polymeric speciesconsisting essentially of olefin monomer units of at least 3 carbonatoms and wherein no more than about 20 mole percent, e.g., 15 to 20mole percent, of the individual molecules of said polymeric species havea molecular weight of less than 500.

[0021] The invention also provides a method for reducing the formationof sludge and the degradation of seals in an engine, comprisinglubricating the engine with the above-described composition.

DETAILED DESCRIPTION OF THE INVENTION

[0022] Oil of Lubricating Viscosity

[0023] The diverse oils of lubricating viscosity include natural andsynthetic lubricating oils and mixtures thereof.

[0024] Natural oils include animal oils and vegetable oils (e.g., castoroil, lard oil) as well as liquid petroleum oils and solvent-treated oracid-treated mineral lubricating oils of the paraffinic, naphthenic ormixed paraffinic-naphthenic types. Oils of lubricating viscosity derivedfrom coal or shale are also useful base oils. Synthetic lubricating oilsinclude hydrocarbon oils such as polymerized and interpolymerizedolefins (e.g., polybutylenes, polypropylenes, propylene-isobutylenecopolymers, poly(1-hexenes, poly(1-octenes), poly(1-decenes), andmixtures thereof); alkylbenzenes (e.g., dodecylbenzenes,tetradecylbenzenes dinonylbenzenes, di(2-ethylhexyl)-benzenes);polyphenyls (e.g., bi-phenyls, terphenyls, alkylated polyphenyls),alkylated diphenyl ethers and alkylated diphenyl sulfides and thederivatives, analogs and homologs thereof.

[0025] Alkylene oxide polymers and interpolymers and derivatives thereofwhere the terminal hydroxyl groups have been modified by, e.g.,estenification or etherification constitute another class of knownsynthetic lubricating oils. These are exemplified by the oils preparedthrough polymerization of ethylene oxide or propylene oxide, the alkyland aryl ethers of these polyoxyalkylene polymers (e.g.,methylpolyisopropylene glycol ether having an average molecular weightof 1,000, diphenyl ether of polyethylene glycol having a molecularweight of 500-1,000, diethyl ether of polypropylene glycol having amolecular weight of 1,000-1,500) or mono- and polycarboxylic estersthereof, for example, the acetic acid esters, mixed C₃-C₈ fatty acidesters, or the C₁₃ Oxo acid diester of tetraethylene glycol.

[0026] Another suitable class of synthetic lubricating oils comprisesthe esters of dicarboxylic acids (e.g., phthalic acid, succinic acid,alkyl succinic acids and alkenyl succinic acids, maleic acid, azelaicacid, suberic acid, sebacic acid, fumaric acid, adipic acid, linoleicacid dimer, malonic acid, alkyl malonic acids, or alkenyl malonic acids)with a variety of alcohols (e.g., butyl alcohol, hexyl alcohol, dodecylalcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycolmonoether, or propylene glycol). Specific examples of these estersinclude dibutyl adipate, di(2-ethylhexyl sebacate, di-n-hexyl fumarate,dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctylphthalate, didecyl phthalate, dieicosyl sebacate, the 2-ethylhexyldiester of linoleic acid dimer, and the complex ester formed by reactingone mole of sebacic acid with two moles of tetraethylene glycol and twomoles of 2-ethylhexanoic acid.

[0027] Esters useful as synthetic oils also include those made from C₅to C₁₂ monocarboxylic acids and polyols and polyol ethers such asneopentyl glycol, trimethylolpropane, pentaerythritol, ordipentaerythritol, tripentaerythritol.

[0028] Unrefined, refined and rerefined oils (and mixtures of each witheach other) of the type disclosed hereinabove can be used in thelubricant compositions of the present invention. Unrefined oils arethose obtained directly from a natural or synthetic source withoutfurther purification treatment. For example, a shale oil obtaineddirectly from retorting operations, a petroleum oil obtained directlyfrom distillation or ester oil obtained directly from an esterificationprocess and used without further treatment would be an unrefined oil.Refined oils are similar to the unrefined oils except that they havebeen further treated in one or more purification steps to improve one ormore properties. Many such purification techniques are known to those ofskill in the art such a solvent extraction, acid or base extraction,filtration, or percolation. Rerefined oils are obtained by processessimilar to those used to obtain refined oils which have been alreadyused in service. Such rerefined oils are also known as reclaimed orreprocessed oils and often are additionally processed by techniquesdirected to removal of spent additives and oil breakdown products.

[0029] The aliphatic and alicyclic substituents, as well as aryl nuclei,are generally described as “hydrocarbon-based” or “hydrocarbyl.” Theseterms are used in their ordinary sense, which is well-known to thoseskilled in the art. Specifically, they refers to a group having a carbonatom directly attached to the remainder of the molecule and havingpredominantly hydrocarbon character. Examples of hydrocarbyl groupsinclude:

[0030] (1) hydrocarbon substituents, that is, aliphatic (e.g., alkyl oralkenyl), alicyclic (e.g., cycloalkyl, cycloalkenyl) substituents, andaromatic-, aliphatic-, and alicyclic-substituted aromatic substituents,as well as cyclic substituents wherein the ring is completed throughanother portion of the molecule (e.g., two substituents together form aring);

[0031] (2) substituted hydrocarbon substituents, that is, substituentscontaining non-hydrocarbon groups which, in the context of thisinvention, do not alter the predominantly hydrocarbon substituent (e.g.,halo (especially chloro and fluoro), hydroxy, alkoxy, mercapto,alkylmercapto, nitro, nitroso, and sulfoxy);

[0032] (3) hetero substituents, that is, substituents which, whilehaving a predominantly hydrocarbon character, in the context of thisinvention, contain other than carbon in a ring or chain otherwisecomposed of carbon atoms. Heteroatoms include sulfur, oxygen, nitrogen,and encompass substituents as pyridyl, furyl, thienyl and imidazolyl. Ingeneral, no more than two, preferably no more than one, non-hydrocarbonsubstituent will be present for every ten carbon atoms in thehydrocarbyl group; typically, there will be no non-hydrocarbonsubstituents in the hydrocarbyl group.

[0033] (I) The Hydrocarbyl-Substituted Succinic Acylating Agent

[0034] The hydrocarbyl-substituted succinic acylating agents are wellknown in the art. See, for example, the following U.S. Patents for theirdisclosures relating to carboxylic acid acylating agents: U.S. Pat. Nos.3,219,666; 3,272,746; 3,381,022; 3,254,025; 3,278,550; 3,288,714,3,271,310; 3,373,111; 3,346,354; 3,272,743; 3,374,174; 3,307,928;3,394,179; and 4,234,435.

[0035] The substituted succinic acylating agents are those which can becharacterized by the presence within their structure of two groups ormoieties. The first group or moiety is referred to herein, forconvenience, as the “substituent group(s)” and is derived from apolyalkene. The polyalkene from which the hydrocarbyl-substituent groupsare derived is characterized by a Mn (number average molecular weight)value. Since the substituent as a whole is normally a mixture ofindividual chains of varying lengths, these substituent groups arecharacterized by having not more than 20 mole percent, preferably notmore than 15 mole percent and most preferably not more than 10 molepercent of individual substituent chains with a Mn of less than 500. Inan alternative embodiment, more than 10 mole percent, and up to 20 molepercent, of the individual substituent chains will have a Mn of lessthan 500, and in another embodiment, 15 to 20 mole percent of theindividual substituent chains will have a Mn of less than 500. Typicallythe substituent groups as a whole will have a Mn value of 1000 to10,000, preferably 1300, 1500, or 2000 to 5000. Most preferably the Mnis at least 2000. In another highly favored embodiment, the substituentgroups will contain not more than 5 mole percent of substituent groupswhich have a Mn of below 300.

[0036] The polyalkenes from which the substituent groups are derived arehomopolymers and interpolymers of polymerizable olefin monomers of 3 to16 carbon atoms; usually 3 to 6 carbon atoms. The interpolymers arethose in which two or more olefin monomers are interpolymerizedaccording to known procedures to form polyalkenes having units withintheir structure derived from each of said two or more olefin monomers.Thus, “interpolymer(s)” as used herein is inclusive of copolymers,terpolymers, tetrapolymers, and higher degree polymers. As will beapparent to those of ordinary skill in the art, the polyalkenes fromwhich the substituent groups are derived are often conventionallyreferred, to as “polyolefin(s)”.

[0037] The olefin monomers from which the polyalkenes are derived arepolymerizable olefin monomers characterized by the presence of one ormore ethylenically unsaturated groups (i.e., >C═C<); that is, they aremono-olefinic monomers such as propylene, 1-butene, isobutene, and1-octene or polyolefinic monomers (usually diolefinic monomers) such as1,3-butadiene, and isoprene. Preferred polyolefins include polybutene,polypropylene, and mixtures thereof. Ethylene polymers are not generallycontemplated for the present invention nor are copolymers of ethylenewith another higher olefin monomer, unless the amount of ethylenemonomer within the polymer is inconsequential, e.g., less than 10percent by weight preferably less than 5%, and more preferably less than2%, and most preferably about 0%. A particularly preferred substituentis derived from polybutene in which at least about 50 mole percent ofthe butene monomer units are isobutylene units.

[0038] These olefin monomers are usually polymerizable terminal olefins;that is, olefins characterized by the presence in their structure of thegroup >C═CH₂. However, polymerizable internal olefin monomers (sometimesreferred to in the patent literature as medial olefins) characterized bythe presence within their structure of the group

[0039] can also be used to form the polyalkenes. When internal olefinmonomers are employed, they normally will be employed with terminalolefins to produce polyalkenes which are interpolymers. For purposes ofthis invention, when a particular polymerized olefin monomer can beclassified as both a terminal olefin and an internal olefin, it will bedeemed to be a terminal olefin. Thus, 1,3-pentadiene (i.e., piperylene)is deemed to be a terminal olefin for purposes of this invention; Thepolyolefins are preferably prepared from predominantly terminal olefins.In this context, “predominantly” means that at least 60% of the olefins,and preferably at least 75% or 90% of the olefins are terminal olefins.

[0040] While the polyalkenes from which the substituent groups of thesuccinic acylating agents are derived generally are hydrocarbonpolyalkenes, they can contain non-hydrocarbon groups such as loweralkoxy, lower alkyl mercapto, hydroxy, mercapto, oxo (i.e., ═O, as inketo and aldehydo groups; e.g.,

[0041] nitro, halo, cyano, carboalkoxy (i.e.,

[0042] where “alkyl” is usually lower alkyl) alkanoyloxy (i.e.,

[0043] where alkyl is usually lower alkyl, provided the non-hydrocarbonsubstituents do not substantially interfere with formation of thesubstituted succinic acid acylating agents of this invention. Whenpresent, such non-hydrocarbon groups normally will not contribute morethan 10% by weight of the total weight of the polyalkenes. Since thepolyalkene can contain such non-hydrocarbon substituent, it is apparentthat the olefin monomers from which the polyalkenes are made can alsocontain such substituents. Normally, however, as a matter ofpracticality and expense, the olefin monomers and the polyalkenes willbe free from non-hydrocarbon groups, except chloro groups which usuallyfacilitate the formation of the substituted succinic acylating agents ofthis invention. (As used herein, the term “lower” when used with achemical group such as in “lower alkyl” or “lower alkoxy” is intended todescribe groups having up to seven carbon atoms.)

[0044] Although the polyalkenes may include aromatic groups (especiallyphenyl groups and lower alkyl- and/or lower alkoxy-substituted phenylgroups such as para-(tert-butyl)phenyl) and cycloaliphatic groups suchas would be obtained from polymerizable cyclic olefins or cycloaliphaticsubstituted-polymerizable acyclic olefins, the polyalkenes usually willbe free from such groups. Nevertheless, polyalkenes derived frominterpolymers of both 1,3-dienes and styrenes such as 1,3-butadiene andstyrene or para-(tert-butyl)styrene are exceptions to thisgeneralization. Again, because aromatic and cycloaliphatic groups can bepresent, the olefin monomers from which the polyalkenes are prepared cancontain aromatic and cycloaliphatic groups.

[0045] From what has been described hereinabove in regard to thepolyalkene, it is clear that there is a general preference foraliphatic, hydrocarbon polyalkenes free from aromatic and cycloaliphaticgroups (other than the diene-styrene interpolymer exception alreadynoted). Within this general preference, there is a further preferencefor polyalkenes which are derived from the group consisting ofhomopolymers and interpolymers of terminal hydrocarbon olefins of 2 to16 carbon atoms. This further preference is qualified by the provisothat, while interpolymers of terminal olefins are usually preferred,interpolymers optionally containing up to 40% of polymer units derivedfrom internal olefins of up to 16 carbon atoms are also with a preferredgroup. A more preferred class of polyalkenes includes those selectedfrom the group consisting of homopolymers and interpolymers of terminalolefins of 2 to 6 carbon atoms, more preferably 2 to 4 carbon atoms.However, another preferred class of polyalkenes are polyalkenes,optionally containing up to 25% of polymer units derived from internalolefins of up to 6 carbon atoms.

[0046] Specific examples of terminal and internal olefin monomers whichcan be used to prepare the polyalkenes according to conventional,well-known polymerization techniques include propylene; 1-butene;2-butene; isobutene; 1-pentene; 1-hexene; 1-heptene; 1-octene; 1-nonene;1-decene; 2-pentene; propylene-tetramer; diisobutylene; isobutylenetrimer; 1,2-butadiene; 1,3-butadiene; 1,2-pentadiene; 1,3-pentadiene;1,4-pentadiene; isoprene; 1,5-hexadiene; 2-methyl-1-heptene;3-cyclohexyl-1-butene; 2-methyl-5-propyl-1-hexene; 3-pentene; 4-octene;3,3-dimethyl-1-pentene; styrene; divinylbenzene; vinyl acetate; allylalcohol; 1-methyl-vinyl acetate; acrylonitrile; ethyl acrylate; methylmethacrylate; ethyl vinyl ether; and methyl vinyl ketone. Of these, thehydrocarbon polymerizable monomers are preferred and of thesehydrocarbon monomers, the terminal olefin monomers are particularlypreferred.

[0047] Specific examples of polyalkenes include polypropylenes,polybutenes, styrene-isobutene copolymers, isobutene-1,3-butadienecopolymers, propene-isoprene copolymers, isobutene-chloroprenecopolymers, isobutene-(para-methyl) styrene copolymers, copolymers of1-hexene with 1,3-hexadiene, copolymers of 1-octene with 1-hexene,copolymers of 1-heptene with 1-pentene, copolymers of 3-methyl-1-butenewith 1-octene, copolymers of 3,3-dimethyl-1-pentene with 1-hexene, andterpolymers of isobutene, styrene and piperylene. More specific examplesof such interpolymers include copolymer of 95% (by weight) of isobutenewith 5% (by weight) of styrene; terpolymer of 95% of isobutene with 2%of 1-butene and 3% of 1-hexene; terpolymer of 60% of isobutene with 20%of 1-pentene and 20% of 1-octene; copolymer of 80% of 1-hexene and 20%of 1-heptene-1; and terpolymer of 90% of isobutene with 2% ofcyclohexene and 8% of propylene. A preferred source of polyalkenes arethe poly(isobutene)s obtained by polymerization of C₄ refinery streamhaving a butene content of 35 to 75 percent by weight and an isobutenecontent of 30 to 60 percent by weight in the presence of a Lewis acidcatalyst such as aluminum trichloride or boron trifluoride. Thesepolybutenes contain predominantly (greater than 80% of the totalrepeating units) of isobutene repeating units of the configuration

[0048] Preparing polyalkenes as described above which meet the variouscriteria for Mn and Mn/Mw, is within the skill of the art. Techniquesreadily apparent to those in the art include controlling polymerizationtemperatures, regulating the amount and type of polymerization initiatorand/or catalyst, and employing chain-terminating groups in thepolymerization procedure.

[0049] A preferred polyalkene is polyisobutene (PBU) prepared bypolymerizing isobutylene. This polyisobutene, as typically prepared,contains of 25.3 mole percent of material having molecular weight below500 and 14.3 mole percent of material having molecular weight below 300.These mole percent values indicate a presence of relatively largeamounts of low molecular weight material, also known as a high presenceof “light ends.” In order to remove the light ends, the polyisobutene issubjected to a stripping at 240° C. and 130 Pa (1 mm Hg). When 8064parts of unstripped polyisobutene are subjected to a stripping under theabove conditions, 227 parts of distillate or light ends are removed.

[0050] Table I presents gel permeation chromatography data of Mn rangesof the unstripped polyisobutene and the stripped polyisobutene. Mnvalues are determined by comparison with a standard broad molecularweight distribution polyisobutylene sample, which in turn isstandardized by comparison with a series of narrow molecular weightdistribution polyisobutylene standards. TABLE I Unstripped PolyisobuteneStripped Polyisobutene {overscore (M)}_(n) weight % mole % weight % mole%  <300 1.6 14.3 0.4 3.9  <500 3.7 25.3 2.4 15.0  500-1000 6.8 18.8 7.021.7 <1000 10.6^(a) 44.1 9.4 36.7 1000-1500 8.9 14.7 9.8 17.8 1500-20009.6 11.2 8.7 11.3 >2000 70.9 30.0 72.1 34.2

[0051] Two types of hydrocarbyl substituted succinic acylating agentsare envisioned as Type A and Type B. The Type A succinic acylating agentis of the formula

[0052] In the above formula, R¹ is the hydrocarbyl based substituent, asdiscussed above, preferably having 40 to 500 carbon atoms and morepreferably 50 to 300 carbon atoms. The Type A hydrocarbyl-substitutedsuccinic acylating agents are prepared by reacting one mole of an olefinpolymer or chlorinated analog thereof with one mole of an unsaturatedcarboxylic acid or derivative thereof such as fumaric acid, maleic acidor maleic anhydride. Typically, the Type A succinic acylating agents arederived from maleic acid, its isomers, anhydride and chloro and bromoderivatives.

[0053] For the Type A succinic acylating agent, the polyalkene fromwhich the substituent groups are derived has an Mn value of generally asdescribed above, that is, 1000 to 10,000. Preferably, the Mn value is1300, 1500, or 1800 to 5000 or 3200, and most preferably 2000 to 2800.

[0054] The Type A succinic acylating agent is characterized by one moleof olefin polymer or chlorinated analog thereof with one mole of anunsaturated carboxylic acid or derivative thereof. The Type B succinicacylating agent, on the other hand, is a polysuccinated acylating agent.The succinic groups correspond to

[0055] and mixtures thereof.

[0056] The Type B succinic acylating agents can be represented by thefollowing

R¹—R²)_(y)

[0057] wherein R¹ represents one molecular weight of substituent group,R² represents one succinic group corresponding to Formula Ib, asdiscussed above, and y is a number equal to or greater than 1.1 or equalto or greater than 1.3. Preferred embodiments of the Type B succinicacylating agents could be represented by, for example, letting R¹ and R²represent preferred substituent groups and succinic groups,respectively, and by letting the value of y vary. In the above formula,y is preferably equal to or greater than 1.4; and more preferably y isequal to or greater than 1.5. As to preferred upper and lower limits, ycan be 1.3 to 3.5, especially 1.4 to 3.5 and most especially 1.5 to 2.5.

[0058] The hydrocarbyl-based substituent used for the Type B succinicacylating agent is generally the same as that which is used for thehydrocarbyl-based substituent used for the Type A succinic acylatingagent. The Mn value for the hydrocarbyl-based substituent for both TypeA and Type B succinic acylating agents is typically 1000 to 10,000, asdescribed above. For the hydrocarbyl-based substituent for the Type Bsuccinic acylating agent, the Mn is preferably 1800 to 3200 and morepreferably 2000 to 2800.

[0059] Specific examples for the preparation of the Type A and Type Bsuccinic acylating agents, respectively, are as follows.

EXAMPLE 1 (COMPARATIVE) (Type A, with Unstripped PBU)

[0060] Added to a 5 liter, 4 neck flask are 2036 parts (1 mole)unstripped PBU and 107.8 (1.1 moles) maleic anhydride. The contents areheated to 138° C. and chlorine gas is blown below the surface over a 5hour period with the chlorine addition being 43 parts (0.61 moles) whileraising the temperature from 138° C. to 165 ° C.; the temperature isthen increased to 182° C. over 2 hours and held at 182° C. for 1 hour.Additional chlorine gas, 42.9 parts (0.60 moles) is blown below thesurface over 5 hours while raising the temperature from 182 to 193° C.The contents are then heated to 196° C. over 1 hour and maintained at196° C. for 5 hours. The contents are stripped at 196° C. and less than1.3 kPa (10 mm Hg). The contents are cooled and bottled to give aproduct having a theoretical total acid number of 51 and theoretical 9%unreacted PBU.

EXAMPLE 2 (Type A, with Stripped PBU)

[0061] The procedure of Example 1 is repeated except that 2300 parts (1mole) stripped PBU, 107.8 parts (1.1 moles) maleic anhydride and a totalof 85.9 parts (1.21 moles) chlorine gas are utilized. The contents havea theoretical total acid number of 47 and theoretical 10% unreacted PBU.

EXAMPLE 3 (COMPARATIVE) (Type B, with Unstripped PBU)

[0062] Charged to a 12 liter, 4-neck flask are 7940 parts (3.9 moles)unstripped PBU and 592 parts (6.05 moles) maleic anhydride. The contentsare heated to 138° C. and chlorine gas is added below the surface over afive-hour period, with the chlorine addition being 234 parts (3.3moles). During this addition, the temperature is uniformly raised from138 to 165° C.; the temperature is then raised from 165 to 182° C. over2 hours and held at 182° C. for 1 hour. While raising the temperaturefrom 182 to 193° C., chlorine gas, 236 parts (3.3 moles) is added belowthe surface. The temperature is increased from 193 to 196° C. over 1hour and held at 196° C. for 5 hours. Afterwards, the contents arestripped at 196° C. and 4 kPa (30 mm Hg) to remove unreacted maleicanhydride. The contents have a 0.207% chlorine, 0.53% free maleicanhydride, and a total acid number of 68.

EXAMPLE 4 (Type B, with Stripped PBU)

[0063] The procedure of Example 2 is repeated except that 7834 parts(3.4 moles) stripped PBU, 517 parts (5.3 moles) maleic anhydride, and atotal of 410 parts (5.8 moles) chlorine gas are utilized. The contentshave a % chlorine of 0.174%, free maleic anhydride of 0.22 and a totalacid number of 60.

[0064] (II) The Polyamine

[0065] Two different types of polyamines are suitable for reacting withthe hydrocarbyl-substituted succinic acylating agent (I). The firstpolyamine is (IIa), a polyalkylene polyamine containing at least oneH—N< group (that is, an amine group containing at least one hydrogen,i.e., a primary or secondary amine), wherein no more than 20 molepercent of the molecules thereof contain 6 or fewer nitrogen atoms, andpreferably no more than 10 or 5 mole percent of the molecules contain 6or fewer nitrogen atoms. This class of polyamines can be represented bythe formula

[0066] in which each R³ is independently hydrogen or an alkyl group of 1to 10 carbon atoms; Z is an alkylene group of 1 to 10 carbon atoms, aheterocyclic nitrogen containing cycloalkylene or an oxyalkylene groupof 1 to 10 carbon atoms and n is a number in the range of 1 to 10,provided that not more than 20 mole percent of the polyamine moleculeshave 6 or fewer nitrogen atoms. In a preferred embodiment, Z is analkylene group and the preferred alkylene is ethylene or propylene.Useful are the alkylene polyamines wherein each R³ is hydrogen with theethylene polyamines, and mixtures of ethylene polyamines areparticularly preferred. Usually n will have an average value of 5 to 7with the understanding that some species of ethylene polyamines whereinn is 1 to 4 may be present, provided that their presence contributes notmore than 20 mole percent molecules with 6 or fewer nitrogen atoms. Suchalkylene polyamines include ethylene polyamines, propylene polyamines,butylene polyamines, pentylene polyamines, hexylene polyamines, andheptylene polyamines. The higher homologs of such amines and relatedaminoalkyl-substituted piperazines are also included.

[0067] Alkylene polyamines that that may be present—but only at thelower levels permitted for the present compositions—include ethylenediamine, triethylene tetramine, propylene diamine, trimethylene diamine,hexamethylene diamine, decamethylene diamine, octamethylene diamine,di(heptamethylene) triamine, tripropylene tetramine, tetraethylenepentamine, trimethylene diamine, pentaethylene hexamine,di(trimethylene) triamine, N-(2-aminoethyl) piperazine, and1,4-bis(2-aminoethyl) piperazine. Higher homologs can be obtained bycondensing two or more of the above-illustrated materials.

[0068] Polyethylene amines (i.e., ethylene polyamines) are preferred,and such polyamines are described in detail under the heading “Diaminesand Higher Amines” in the Encyclopedia of Chemical Technology, SecondEdition, Kirk and Othmer, Volume 7, pages 27-39, IntrasciencePublishers, Division of John Wiley and Sons, 1965. Such compounds areprepared most conveniently by the reaction of an alkylene chloride withammonia or by reaction of an ethylene imine with a ring-opening reagentsuch as ammonia. These reactions result in the production of thesomewhat complex mixtures of alkylene polyamines, including cycliccondensation products such as piperazines.

[0069] The polyalkylene polyamines (IIa) which are particularly suitablefor the present invention can be obtained by subjecting a standardpolyamine mixture containing at least 40 percent by weight of materialsof 7 nitrogen atoms or more, to a stripping procedure. Such a standardpolyamine mixture would typically have 60 weight percent materialscontaining 6 or fewer nitrogen atoms. Lower molecular weight polyaminesand volatile contaminates are thereby removed from this alkylenepolyamine mixture to leave as residue what is sometimes termed“polyamine bottoms” (although sometimes this term is used commerciallyto refer to unstripped materials). In general, stripped alkylenepolyamine bottoms can be characterized as having less than 20 molepercent of polyamine components containing 6 or fewer nitrogen atoms,preferably less than 10 mole percent of polyamine components of six orfewer nitrogen atoms, and most preferably less than 5 mole percent ofpolyamine components of six or fewer nitrogen atoms.

[0070] Table II, below, defines the polyethylene polyamine profile of astandard, commercial polyethylene polyamine composition in comparison totwo stripped polyethylene polyamines. The values represented are averagevalues. TABLE II # of N Atoms from Formula IIa Source of PolyethylenePolyamine: ≦4 5 6 7 Standard Polyamine 3.2 14.6 46.0 36.2 StandardPolyamine (HPA-X ™) 1.41 16.35 41.64 40.60 Stripped Polyamine “X” 0.150.81 4.19 94.85 Stripped Polyamine “PF” 0.62 0.50 5.03 93.85

[0071] The second polyamine IIb is a condensed polyamine, that is, acondensate formed by reacting (i) a polyalkylene amine containing atleast one H—N< group (as described above) with (ii) at least one alcoholcontaining at least one ether group, amine group, nitro group, oradditional alcohol group. Such alcohols of (ii) can be expressedgenerally by the formula

R¹ _(m)X—R²—(R³OH)_(n)

[0072] wherein:

[0073] X is O or N;

[0074] m is 1 when X is O and 2 when X is N;

[0075] each R¹ is independently hydrogen, a hydrocarbyl group, ahydroxy-hydrocarbyl group, or, if X is N, each R¹ can be O so as to forma NO₂ group;

[0076] R² is a hydrocarbylene group or an ether-containing group, havingn+1 sites of linkage

[0077] R³ is an alkylene group of 1 to about 4 carbon atoms; and

[0078] n is 1, 2, or 3.

[0079] The hydrocarbylene group R² is a hydrocarbyl group orether-containing group which, as stated above, has sufficient valencesor sites of linkage to bond to the R¹ _(m)X group and 1, 2, or 3 R³OHgroups. Thus this term is used in a somewhat broader sense than theanalogous term “alkylene,” which is sometimes used to represent a grouphaving only two sites of linkage (e.g., methylene, —CH₂—; propylene,—CH(CH₃)—CH₂—.) Also included within the scope of this definition of“hydrocarbylene” as applied to R² is the possibility that, when n=3, theR² can represent a central carbon atom without additional hydrogen orhydrocarbyl substituents, as follows:

[0080] A general alternative term which might be used in this context inplace of “hydrocarbylene” would be “carbon-based linking group.”

[0081] Such condensed polyamines and methods for their preparation aredescribed in U.S. Pat. Nos. 4,477,362, 5,368,615, and 5,053,152. Inthese and related patents, a variety of formulas and definitions havebeen used to describe the condensed materials and in particular theiralcohol components. At least two alternative definitions of the alcoholcomponent may be useful for illustrating a part of the breadth of thepresent invention. Thus, one embodiment of the alcohol can be thatexpressed below as Formula IIb1:

HO—(R⁵O—)_(p)R⁶—OR⁷  Formula IIb1

[0082] wherein R⁵ and R are independently alkylene groups of 2 to 8carbon atoms, R⁷ is aryl, hydrocarbyl-substituted aryl, alkyl oraralkyl, and p is 0 to 8. Another expression is in Formula IIb2:

(R⁸)_(q)—Y—X—(AOH)_(m)  Formula IIb2

[0083] wherein R⁸ is independently hydrogen or a hydrocarbyl group, Yrepresents nitrogen or oxygen, X is a hydrocarbon-based group, A is analkylene group containing 1 to 4 carbon atoms, q is 1 or 2, dependentupon the valence of Y, and m is 1, 2 or 3. Among these types of hydroxycompounds that can react with the polyamine to form the condensedpolyamine, the hydroxy compound of Formula IIb1 can be an alkoxylatedmonohydroxy compound and the hydroxy compound of Formula IIb2 can be apolyhydroxy compound (polyol).

[0084] The hydroxy compounds of Formula IIb1 can be polyoxyalkylenealcohols (sometimes called polyglycols). Preferably R⁵ and R⁶ are eachindependently ethylene, propylene or butylene groups such that thesehydroxy compounds are polyoxyethylene alcohols, polyoxypropylenealcohols and polyoxybutylene alcohols. These polyoxyalkylene alcoholscan contain up to 150 oxyalkylene groups, with the alkylene groupcontaining from 2 to 8 carbon atoms. Such polyoxyalkylene alcohols aregenerally dihydric alcohols. That is, each end of the moleculeterminates with an OH group. Any remaining OH group(s) are esterifiedwith a monobasic, aliphatic or aromatic carboxylic acid of up to 20carbon atoms such as acetic acid, propionic acid, oleic acid, stearicacid, and benzoic acid. The monoethers of these alkylene glycols andpolyoxyalkylene glycols are also useful. These include the monoarylethers, monoalkyl ethers, and monoaralkyl ethers of these alkyleneglycols and polyoxyalkylene glycols.

[0085] Within Formula IIb1, R⁵ and R⁶ are independently alkylene groupsof 2 to 8 carbon atoms and preferably are ethylene groups; and R⁷ isaryl (e.g., phenyl), lower alkoxy phenyl, or lower alkyl phenyl, orlower alkyl (e.g., ethyl, propyl, t-butyl, pentyl); and aralkyl (e.g.,benzyl, phenethyl, phenylpropyl, pethylphenethyl); p is from zero toeight, preferably from 2 to 4. Polyoxyalkylene glycols in which thealklylene groups are ethylene or propylene and p is at least 2, as wellas the monoethers thereof as described above, are particularly useful.

[0086] The polyhydroxy alcohols of Formula IIb2can contain 2 to 10hydroxy groups. These are illustrated, for example, by the alkyleneglycols and polyoxyalkylene glycols mentioned above such as ethyleneglycol, diethylene glycol, triethylene glycol, tripropylene glycol,dibutylene glycol, tributylene glycol, and other alkylene glycols andpolyoxyalkylene glycols in which the alkylene groups contain from 2 to 8carbon atoms.

[0087] Useful alcohols also include those polyhydric alcohols containingup to 12 carbon atoms, and especially those containing 3 to 10 carbonatoms. This class of alcohols includes glycerol, trimethylolpropane,erythritol, pentaerythritol, dipentaerythritol, gluconic acid,glyceraldehyde, glucose, arabinose, 1,7-heptanediol, 2,4-heptanediol,1,2,3-hexanetriol, 1,2,4-hexanetriol, 1,2,5-hexanetriol,2,3,4-hexanetriol, 1,2,3-butanetriol, quinic acid, 2,2,6,6-tetrakis(hydroxymethyl) cyclohexanol, 1,10-decanediol, and digitalose. Aliphaticalcohols containing at least 3 hydroxyl groups and up to 10 carbon atomsare useful. Among the most preferred hydroxy compounds of Formula IIb2are those in which R⁸ is hydrogen, Y is oxygen, X is —CCH₂—, A is —CH₂—,q is 1, and m is 3, which gives pentaerythritol; and those in which R⁸is hydrogen, Y is nitrogen, X is —C—, A is —CH₂—, q is 2, and m is 3,which gives tris(hydroxymethyl) aminomethane (THAM). Also useful aretris(hydroxyethyl) aminomethane, diethanolamine, and triethanolamine.

[0088] In preparing the condensed polyamine it is not necessary toutilize a stripped or deep stripped polyethylene polyamine to react withthe hydroxy compound. Standard polyethylene polyamines can be used.After the condensed polyamine is prepared, however, it may be necessaryto subject the condensed polyamine to stripping so that the condensedpolyamine contains less than 20 mole percent of components of 6 or fewernitrogen atoms. Usually when the polyamines are reacted with any of theabove hydroxy compounds, the light end components that are present inthe polyamine will react with the hydroxy compound and condense. Thecondensation reaction can be monitored by the amount of water formed.For example, when 3 moles of diethylenetriamine are reacted with 1 moleof pentaerythritol, the condensed polyamine reaction product willcontain 9 nitrogen atoms, shown below in somewhat idealized fashion:

[0089] The following are the preparation of the condensed polyaminesusing a hydroxy compound of Formula IIb2.

EXAMPLE 5

[0090] A mixture of 1000 parts of HPA-X™ (a product of Union Carbideidentified as a polyamine bottoms product having a nitrogen content of31.5% by weight and an average base number of 1180) and 613 parts byweight of trishydroxymethyl aminomethane (“THAM”) are heated and stirredto 82° C. Added are 15.9 parts of an 85% by weight phosphoric acidaqueous solution and the contents are heated to 229° C. The contents areheld at 229° C. for 10 hours to form a condensed polyamine. When the 10hour hold is completed, low molecular weight amines are removed over a 6hour period while maintaining the temperature at 235° C. At the end ofthe 6 hour hold, the contents are cooled to 93° C. and added is 22.1parts of a 50% weight aqueous solution of sodium hydroxide. Theresulting product is a condensed polyamine having the followingproperties: viscosity at 100° C. of 90 cSt; total base number of 730 andnitrogen content of 27%.

EXAMPLE 6

[0091] The procedure of Example 5 is repeated except that 690 partspentaerythritol is used in place of the THAM to form a condensedpolyamine.

[0092] The composition of this invention comprises the reaction productof (I) the acylating agent with (II) the polyamine to form thenitrogen-containing dispersant. The acylating agent and the polyamineare reacted in amounts sufficient to provide from one-half equivalent to2 equivalents of polyamine per equivalent of acylating agent. Anequivalent of polyamine is that amount of amine divided by the totalnumber of nitrogen atoms present. Thus, a pure pentaethylenehexamine(PEHA) has an equivalent weight equal to its molecular weight divided bythe 6 nitrogen atoms present, or 232÷6=38.67 equivalent weight. Sincepolyamines are usually a mixture, a more reliable method is to use the %nitrogen of the polyamine to determine equivalent weight, thus pure PEHAhas a % nitrogen of 36.21 and the equivalent weight of PEHA isdetermined by dividing 100× the molecular weight of nitrogen (1400) bythe % N in the sample. Thus using this method, the equivalent weight ofPEHA is, again, 1400÷36.21=38.67.

[0093] The number of equivalents of acylating agent depends on thenumber of carboxylic functions present as the succinic groups of FormulaIb. In general, however, there are two equivalents of acylating agentfor each succinic group in the acylating agents. A conventionaltechnique used to determine the number of carboxyl functions in theacylating agent is an acid number. The equivalent weight of theacylating agent using the acid number of the acylating agent isdetermined by dividing 56,100 by the acid number. Thus, an acylatingagent having an acid number of 68 has for its equivalent weight56,100÷68=825.

EXAMPLE 7 (COMPARATIVE)

[0094] Charged to a 12 liter, 4 neck round bottom flask are 2640 parts(3.2 equivalents) of the alkenyl substituted succinic anhydride madefrom unstripped PBU as per Example 3 and 2784 parts diluent oil. Thecontents are heated to 110° C. and 172.6 parts (4.16 equivalents) ofHPA-X polyamines identified in Example 5 (not condensed) are added in 1hour. This polyamine contains 41.6 mole percent of polyamine componentshaving 6 or fewer nitrogen atoms. The temperature is increased to 155°C. and held there for 5 hours while blowing with nitrogen at 14 L/hour(0.5 cubic feet per hour). The contents are then filtered using afiltering aid to give a product having 0.982% nitrogen, a total acidnumber of 1.62 and total base number of 20.0.

EXAMPLE 8 (COMPARATIVE)

[0095] Charged to a 12 liter, 4 neck round bottom flask are 2618 parts(2.8 equivalents) of the alkenyl substituted succinic anhydride madefrom stripped PBU as prepared in Example 4 and 2744 parts diluent oil.The contents are heated to 110° C. and 151.1 parts (3.64 equivalents)HPA-X™ polyamines are added in 1.5 hours. The temperature is increasedto 155° C. and held there for 5 hours while blowing with nitrogen at 14L/hr (0.5 cubic feet per hour). The contents are then filtered with afiltering aid to give a product having 0.862% nitrogen, a total acidnumber of 1.33 and a total base number of 17.70.

EXAMPLE 9 (COMPARATIVE)

[0096] Charged to a 12 liter, 4 neck round bottom flask are 2252 parts(2.73 equivalents) of the unstripped alkenyl substituted succinicanhydride as prepared in Example 3 and 2383 parts diluent oil. Thecontents are heated to 110° C. and 154.1 parts (3.55 equivalents) of astripped polyamine are added in 1 hour. The polyamine has 4.19 molepercent components of 6 or fewer nitrogen atoms. The temperature isincreased to 155° C. and held there for 5 hours while blowing withnitrogen at 14 L/hr (0.5 cubic feet per hour). The contents are thenfiltered using a filtering aid to give a product having 0.951% nitrogen,a total acid number of 2.49 and a total base number of 20.0.

EXAMPLE 10

[0097] Charged to a 12 liter, 4 neck round bottom flask are 2431 parts(2.6 equivalents) of the alkenyl substituted succinic anhydride madefrom stripped PBU as prepared in Example 4 and 2554 parts diluent oil.The contents are heated to 110° C. and 146.7 parts (3.38 equivalents) ofthe stripped polyamine used in Example 9 are added in 1 hour. Thetemperature is increased to 155° C. and held there for 5 hours whileblowing with nitrogen at 14 L/hr (0.5 cubic feet per hour). The contentsare filtered using a filtering aid to give a product having 0.89%nitrogen, total acid number of 1.99 and total base number of 16.20.

EXAMPLE 11 (COMPARATIVE)

[0098] Charged to a 12 liter, 4 neck round bottom flask are 3094 parts(3.75 equivalents) of the unstripped alkenyl substituted succinicanhydride as prepared in Example 3 and 3286 parts diluent oil. Thecontents are heated to 110° C. and 256.2 parts (4.88 equivalents) of thecondensed polyamine as prepared in Example 5 are added in 1 hour. It iscalculated that the condensed polyamine has 41.6 mole percent polyaminecomponents of 6 or fewer nitrogen atoms. The temperature is increased to155° C. and held there for 5 hours while blowing with nitrogen at 14L/hr (0.5 cubic feet per hour). The contents are then filtered using afiltering aid to give a product having 0.997% nitrogen, a total acidnumber of 3.79 and a total base number of 16.85.

EXAMPLE 12

[0099] Charged to a 12 liter, 4 neck round bottom flask are 2785 parts(2.98 equivalents) of the alkenyl substituted succinic anhydride madefrom stripped PBU as prepared in Example 4 and 2938 parts diluent oil.The contents are heated to 110° C. and 203.2 parts (3.87 equivalents) ofthe condensed polyamine used in Example 11 are added in 1 hour. Thetemperature is increased to 155° C. and held there for 5 hours whileblowing with nitrogen at 14 L/hr (0.5 cubic feet per hour). The contentsare filtered using a filtering aid to give a product having 0.89%nitrogen, total acid number of 3.66 and total base number of 13.7.

[0100] The following is the preparation of the sludge preventing/sealprotecting additive of a nitrogen containing dispersant based upon thereaction of (I) and (II):

[0101] The reaction products of various combinations of (I) and (II) asset forth above are blended with other conventional components typicalof a heavy-duty diesel lubricant formulation (in a Group II basestock),to give a series of test samples. The amount of the dispersant to betested in each case is 7.2% by weight (including about 50% diluent oil)of the test sample. The test samples are evaluated in the Volkswagen™PV3344 Viton™ Seal Test. This test is designed to test compatibility ofa crankcase lubricating oil that contains nitrogen-containingdispersants, that is, the reaction product of (I) and (II).

[0102] The elastomer tested is the Parker-Pradifa™ SRE AK6, which alsohas the designation FKM E-281. Prior to the test, the elastomerspecimens are thermally conditioned at 150° C. for 48 hours in order todrive off moisture which is readily absorbed by the filler component ofthis elastomer.

[0103] A thermally-conditioned elastomer specimen is immersed into avolume of the test sample such that the volume of the sample:volume ofthe elastomer is approximately 85:1. The immersion test temperature is150° C. and the immersion period is a total of 282 hours made up ofthree 94-hour periods. After the first two 94-hour periods, the testsample is replaced with a fresh test sample. At the completion of the282-hour period, the elastomer specimens are evaluated for tensilestrength, percent elongation, and cracking. Normal performance standardsfor this test are that the tensile strength be at least 8 newtons persquare millimeter; the elongation at rupture be at least 160 percent,and there be no evidence of cracking (or alternatively “barely” evidenceof cracking). Even better performance is indicated by a percentelongation of at least 190%.

[0104] Different specimens of the same samples (prepared in Group I basestocks and employing a slightly different concentration of viscositymodifier) are evaluated for soot handling capability using anaccelerated version of the Mack™ T-8 test (in which soot is generated ata faster rate and using a reduced oil charged, compared with thestandard test). For each sample, rotational viscosity is measured usinga controlled stress rheometer with cone-and-plate geometry at 10 S⁻¹ at100° C. Viscosity is plotted as a function of the percent soot in thesample. In each plot the viscosity begins to increase more or lessabruptly above a certain soot concentration, from a base value of about11 to 18 mPa·s (cP) at lower soot concentrations. In the table below,the value for “max. soot” is reported as the approximate concentration,by interpolation, at which the viscosity has increased to 50 mPa·s (cP).Higher “max. soot” values represent greater effectiveness in dispersancyand soot handling ability. Prod. of Max Soot Tensile Strength ElongationEx. No. % (N/mm²) % Cracking 7 6.2 6.7 156.3 moderate 9 5.3 6.3 142.7moderate 11 4.5 8.0 182.4 none 8 5.8 8.7 188.6 barely 10 5.7 8.3 204.4barely 12 4.5 10.6 224.9 none

[0105] The results show that the compositions of the present invention(10 and 12) exhibit excellent seal performance. The product of Ex. 10(using stripped polyisobutylene and stripped amines) also exhibitsexcellent soot handling performance. Common experience, to the contrary,indicates that modifications which improve seal performance tend to leadto poorer soot handling abilities. The material of Example 12 (usingstripped polyisobutylene and condensed amine) shows outstanding sealperformance, although reduced soot handling ability at the concentrationemployed. It is believed that the much higher molecular weight of thecondensed amine results in a lower molar concentration of thedispersant, and the results should significantly improve with suitableincrease in total concentration.

[0106] Testing of additional samples (also containing about 7%dispersant, which however may not be directly comparable to the samplesreported above due to variations in the conventional additive package)further reveals the excellent seal performance of the compositions ofthe present invention (Examples 22 and 23). (It is noted that thosecompositions with dispersants having CO:N equivalent ratios whichindicate the presence of relatively more N overall tend to exhibit moresevere problems with seals, and for these materials the presentinvention is especially desirable.) type of polybutene/type of amineTensile Elongation Ex in dispersant Strength % Cracking 13unstripped/typical (HPA-X)^(a) 7.0 177 severe 14 unstripped/typical(HPA-X)^(b) 8.5 199 barely 15 unstripped/heavy (1:1 X:PF)^(c) 5.6 148severe 16^(d) unstripped/heavy (1:1 X:PF)^(c) 6.6 180 severe 17unstripped/heavy (1:1 X:PF)^(a) 6.3 164 severe 18 unstripped/heavy(PF)^(c) 6.0 159 severe 19^(d) unstripped/heavy (PF)^(c) 7.0 190moderate 20 unstripped/heavy (PF)^(a) 5.4 135 severe 21 stripped/typical(HPA-X)^(c) 7.0 167 barely 22 stripped/heavy (1:1 X:PF)^(c) 8.8 209 none23 stripped/heavy (PF)^(c) 9.5 220 none

[0107] The compositions of the present invention are useful in crankcaselubricants for spark-ignited and compression-ignited internal combustionengines, including automobile and truck engines, two-cycle engines,aviation piston engines, and marine and railroad diesel engines. Theycan also be used in gas engines, stationary power engines and turbines.Automatic transmission fluids, transaxle lubricants, gear lubricants,metal-working lubricants, hydraulic fluids and other lubricating oil andgrease compositions can also benefit from the incorporation therein ofthe compositions of the present invention.

[0108] While the invention has been explained in relation to itspreferred embodiments, it is to be understood that various modificationsthereof will become apparent to those skilled in the art upon readingthe disclosure. Therefore, it is to be understood that the inventiondisclosed herein is intended to cover such modifications as fall withinthe scope of the appended claims.

[0109] It is believed that some of the materials described above mayinteract in the final formulation, so that the components of the finalformulation may be different from those that are initially added. Forinstance, metal ions (of, e.g., a detergent) can migrate to other acidicsites of other molecules. The products formed thereby, including theproducts formed upon employing the composition of the present inventionin its intended use, may not susceptible of easy description.Nevertheless, all such modifications and reaction products are includedwithin the scope of the present invention; the present inventionencompasses the composition prepared by admixing the componentsdescribed above.

[0110] Each of the documents referred to above is incorporated herein byreference. Except in the Examples, or where otherwise explicitlyindicated, all numerical quantities in this description specifyingamounts of materials, reaction conditions, molecular weights, number ofcarbon atoms, and the like, are to be understood as modified by the word“about.” Unless otherwise indicated, each chemical or compositionreferred to herein should be interpreted as being a commercial gradematerial which may contain the isomers, by-products, derivatives, andother such materials which are normally understood to be present in thecommercial grade. However, the amount of each chemical component ispresented exclusive of any solvent or diluent oil which may becustomarily present in the commercial material, unless otherwiseindicated. It is to be understood that the upper and lower amount,range, and ratio limits set forth herein may be independently combined.As used herein, the expression “consisting essentially of” permits theinclusion of amounts of substances which do not materially affect thebasic and novel characteristics of the composition under consideration.

What is claimed is:
 1. A composition suitable for reducing engine sludgeand degradation of elastomer seals comprising a major amount of an oilof lubricating viscosity and a minor amount of a nitrogen-containingdispersant wherein the nitrogen containing dispersant is a reactionproduct of (I) a hydrocarbyl-substituted succinic acylating agent,wherein 15 to about 20 mole percent of the individual molecules thereofhave a hydrocalbyl substituent with a molecular weight of less than 500;wherein the hydrocarbyl substituent is a polymeric species consistingessentially of olefin monomer units of at least 3 carbon atoms; and (II)at least one polyamine, wherein the polyamine is (a) a polyalkyleneamine containing at least one H—N< group; or (b) a condensate of (i) apolyalkylene amine containing at least one H—N< group with (ii) at leastone alcohol containing at least one ether group, amine group, nitrogroup, or additional alcohol group; wherein in said polyamine (a) orcondensed polyamine (b) no more than about 20 mole percent of themolecules contain 6 or fewer nitrogen atoms.
 2. The composition of claim1 wherein the substituent groups in (I) are derived from a polyalkenecharacterized by a Mn value of about 1000 to about 10,000.
 3. Thecomposition of claim 2 wherein Mn is at least about
 2000. 4. Thecomposition of claim 1 wherein the substituent groups in (I) are derivedfrom one or more homopolymers or copolymers of olefins of 3 to about 16carbon atoms.
 5. The composition of claim 4 wherein the olefins arepredominantly terminal olefins.
 6. The composition of claim 4 whereinthe substituent groups are derived from one or more homopolymers orcopolymers of olefins of 3 to about 6 carbon atoms.
 7. The compositionof claim 6 wherein the substituent groups are derived from polybutene,polypropylene, or mixtures thereof.
 8. The composition of claim 6wherein the substituent groups are derived from polybutene in which atleast about 50 mole percent of the monomer units are isobutylene units9. The composition of claim 1 wherein the acylating agent ischaracterized by the presence within its structure of an average of atleast about 1.1 succinic groups for each equivalent weight ofsubstituent groups.
 10. The composition of claim 1 wherein the acylatingagent is characterized by the presence within its structure of anaverage of at least about 1.3 succinic groups for each equivalent weightof substituent groups.
 11. The composition of claim 1 wherein thealkylene moiety of the polyalkylene amine of (IIa) or (IIb) is ethylene.12. The composition of claim 1 wherein for (IIa), less than about 10mole percent of the polyamine molecules contain six or fewer nitrogenatoms.
 13. The composition of claim 1 wherein for (IIa) less than about5 mole percent of polyamine molecules contain six or fewer nitrogenatoms.
 14. The composition of claim 1 wherein the alcohol of II(b)(ii)is of the formula R¹ _(m)X—R²—(R³OH)_(n) wherein: X is O or N; m is 1when X is O and 2 when X is N; each R¹ is independently hydrogen, ahydrocarbyl group, a hydroxy-hydrocarbyl group, or, if X is N, each R¹can be O so as to form a NO₂ group; R² is a hydrocarbylene group or anether-containing group, having n+1 sites of linkage R³ is an alkylenegroup of 1 to about 4 carbon atoms; and n is 1, 2, or
 3. 15. Thecomposition of claim 1 wherein the alcohol of II(b)(ii) is a di- ortri-ethanolamine.
 16. The composition of claim 1 wherein the alcohol ofII(b)(ii) is trimethylolpropane.
 17. The composition of claim 1 whereinthe alcohol of II(b)(ii) is pentaerythritol.
 18. The composition ofclaim 1 wherein the alcohol of II(b)(ii) is tris(hydroxymethyl)aminomethane.
 19. The composition of claim 1 wherein the alcohol of II(b)(ii)is tris(hydroxyethyl)amino methane.
 20. The composition of claim 1wherein the alcohol of II(b)(ii) is a polyoxyalkylene alcohol.
 21. Thecomposition of claim 1 wherein within (IIb) the condensed polyamine isprepared by reacting about 1 to about 3 equivalent of the polyamine with1 equivalent of the alcohol in the presence of an acid catalyst.
 22. Thecomposition of claim 1 wherein the nitrogen-containing dispersant isprepared by reacting (I) the hydrocarbyl-substituted succinic acylatingagent with (IIa) the polyethylene polyamines.
 23. The composition ofclaim 1 wherein the nitrogen-containing dispersant is prepared byreacting (I) the hydrocarbyl-substituted succinic acylating agent with(IIb) the condensed polyamine.
 24. A method for reducing the formationof sludge and the degradation of seals in an engine, comprisinglubricating said engine with the composition of claim
 1. 25. Acomposition suitable for reducing engine sludge and degradation ofelastomer seals comprising a major amount of an oil of lubricatingviscosity and a minor amount of a nitrogen-containing dispersant whereinthe nitrogen containing dispersant is a reaction product of (I) ahydrocarbyl-substituted succinic acylating agent wherein the hydrocarbylsubstituent is prepared from a polymeric species consisting essentiallyof olefin monomer units of at least 3 carbon atoms and wherein 15 toabout 20 mole percent of the individual molecules of said polymericspecies have a molecular weight of less than 500; and (II) at least onepolyamine, wherein the polyamine is (a) a polyalkylene amine containingat least one H—N< group; or (b) a condensate of (i) a polyalkylene aminecontaining at least one H—N< group with (ii) at least one alcoholcontaining at least one ether group, amine group, nitro group, oradditional alcohol group; wherein in said polyamine (a) or condensedpolyamine (b) no more than about 20 mole percent of the moleculescontain 6 or fewer nitrogen atoms.